Ac refrigerant circuit

ABSTRACT

A number of variations may include a refrigeration circuit which may include a compressor operably coupled to an evaporator. Additionally, a compressor may be operably coupled to the evaporator using the suction line. Moreover, the suction line may include a pressure sensor and a temperature sensor.

TECHNICAL FIELD

The field to which the disclosure generally relates to includesrefrigerant circuits and methods of making and using the same.

BACKGROUND

Refrigeration circuits may include various designs in order to measureor predict characteristics of the refrigeration circuit.

SUMMARY OF ILLUSTRATIVE VARIATIONS

A number of variations may include a refrigeration circuit which mayhave a condenser which may be operably coupled to an evaporator via aliquid line and expansion valve. Additionally, a compressor may beoperably coupled to the evaporator using a suction line. Moreover, thesuction line may include a pressure sensor and a temperature sensor.

A number of other variations may include a system which may include acondenser. The condenser may be operably coupled to an evaporator via aliquid line and expansion valve. Moreover, a compressor may be operablycoupled to the evaporator via a suction line. Additionally, a pressuresensor and a temperature sensor may be disposed in the suction line.

Yet a number of other variations may include a method which may includefirst providing a refrigeration circuit. The refrigeration circuit mayinclude a condenser operably coupled to an evaporator and may furtherinclude a compressor operably coupled to the evaporator. The compressormay be operably coupled to the evaporator via a suction line. Next, botha pressure and a temperature may be directly measured in the suctionline.

Other illustrative variations within the scope of the invention willbecome apparent from the detailed description provided hereinafter. Itshould be understood that the detailed description and specificexamples, while disclosing variations within the scope of the invention,are intended for purposes of illustration only and are not intended tolimit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Select examples of variations within the scope of the invention willbecome more fully understood from the detailed description and theaccompanying drawings, wherein:

FIG. 1 is a schematic illustration of a system according to a number ofvariations.

DETAILED DESCRIPTION OF ILLUSTRATIVE VARIATIONS

The following description of the variations is merely illustrative innature and is in no way intended to limit the scope of the invention,its application, or uses.

Referring now to the variation illustrated in FIG. 1, a refrigerationcircuit 10 which may include a condenser 12. The condenser 12 may beoperably coupled to an evaporator 14. Additionally, a compressor 16 maybe operably coupled to the evaporator 14 using a suction line 18. It iscontemplated that the suction line 18 may include a pressure sensor 20and a temperature sensor 22.

Referring again the variation illustrated in FIG. 1, a system 30 may beprovided. The system 30 may be a refrigerant system, or any other systemas known by one of ordinary skill in the art. Additionally, it iscontemplated that the system 30 may be a closed circuit. It is alsocontemplated that the system 30 may be an AC refrigeration circuit orother circuit as known by one of ordinary skill in the art.

Referring again to the variation illustrated in FIG. 1, therefrigeration circuit 10 may include the evaporator 14. It iscontemplated that the evaporator 14 may be any type of evaporator asknown by one of ordinary skill in the art including but not limited to aforced circulation evaporator, a failing film evaporator or a risingfilm evaporator. It is additionally contemplated that the evaporator 14may be constructed and arranged to turn a working fluid from a liquidform into its gaseous form. It is contemplated that the evaporator 14may also include an inlet 32 and an outlet 34 for inlet and outlet ofthe working fluid. Moreover, a sensor 36 may be disposed on any portionof the evaporator 14 including the inlet 32, the outlet 34 or the mainportion of the evaporator 14. The sensor may be a pressure sensor, atemperature sensor, a combination sensor or any other sensor as known byone of ordinary skill in the art.

Referring again to the variation illustrated in FIG. 1, it iscontemplated that the compressor 16 may be any type of compressor asknown by one of ordinary skill in the art including but not limited to acentral fugal compressor, a diagonal or mixed flow compressor, an axialflow compressor, a rotary screw compressor, an air bubble compressor,hermetically sealed, open, or semi-hermetically sealed compressor. It iscontemplated that the compressor 16 may include at least one inlet 38and at least one outlet 40. Moreover, the compressor 16 may be operablycoupled to the evaporator 14 using the suction line 18. The suction line18 may be constructed and arranged to move the working fluid from theevaporator 14 to the inlet 38 of the compressor 16. It is contemplatedthat the working fluid may be a vapor when the working fluid is flowingthrough the suction line 18. It is additionally contemplated that thesuction line 18 may include at least one direct measuring apparatus. Thedirect measuring apparatus may be a pressure sensor 20, a temperaturesensor 22, a combination sensor, or any other sensor as known by one ofordinary skill in the art. It is contemplated that by directly measuringthe temperature and pressure in the suction line 18, compressor failuresalong with a core freezing condition may be avoided.

Referring again to the variation illustrated in FIG. 1, the outlet 40 ofthe compressor 16 may be operably coupled to a discharge line 42.Additionally, the discharge line 42 may be operably coupled to thecondenser 12. It is contemplated that the condenser 12 may be any typeof condenser as known by one of ordinary skill in the art including asurface condenser, a condenser unit, or a direct contact condenser. Thecondenser 12 may be constructed and arranged to condense the workingfluid from the discharge line 42 into a liquid form. When the workingfluid is changed into a liquid, latent heat may be given up by theworking fluid.

Referring again to the variation illustrated in FIG. 1, the dischargeline 42 may include at least one direct measuring device 44. It iscontemplated that the direct measuring device 44 may be a temperaturesensor, a pressure sensor, or any other sensor as known by one ofordinary skill in the art. It is additionally contemplated that thedischarge line 42 may not include a pressure sensor. In the variationwhere no pressure sensor is disposed in the discharge line 42, thepressure of the discharge line 42 may be estimated or determined basedon an algorithm or other indirect sensing methods as known by one ofordinary skill in the art.

Referring again to the variation illustrated in FIG. 1, it iscontemplated that the direct measuring device may be operably coupled toa controller. The direct measuring device may send information that isdirectly, or indirectly sensed to the controller. The controller may beconstructed and arranged to use information from the direct measuringdevice to determine directly or indirectly whether a core freezecondition may occur. It is contemplated that a core freeze condition mayoccur when the compressor 16 control allows a low evaporator pressureand/or pumps liquid working fluid through the compressor 16 or at otherconditions as known by one of ordinary skill in the art. By using thedirect measuring device at the suction line 18, the controller maydetermine if the working fluid is at optimal conditions for theevaporator 14. If the controller determines the working fluid is not atoptimal or near optimal conditions, the controller may stop or otherwisecontrol the system to prevent the core freeze condition or otherundesirable conditions.

Moreover, the condenser 12 may be operably coupled to the evaporator 14using a liquid line 46. The liquid line 46 may be constructed andarranged to move the working fluid from the condenser 12 to theevaporator 14 using an expansion valve 53.

It is contemplated that the direct measuring device and the controllermay be constructed and arranged to control the working fluid usingvarious algorithms. The algorithms may include and are not limited to acombo sensor compressor torque algorithm, a combo sensor low chargealgorithm, and a combo sensor evaporator capacity algorithm.

It is contemplated that the combo sensor compression torque algorithmmay begin by inputting a compressor inlet temperature, working fluidtemperature, RPM, an outlet temperature, or other input which may bedirectly or indirectly measured or sensed in the system. The sensed ormeasured features may then be input into Step 1 where Step 1 may computea compressor inlet super heat by using the compressor pressure and thecompressor temperature. The inlet superheat may then be moved into Step2. Step 2 may also include an additional input of the compressorsisentropic efficiency which may be calculated or sensed based on any ofthe other inputs including but not limited to compressor inlettemperature, compressor inlet pressure, RPMs, or compressor outlettemperature. Step 2 may compute the compressor outlet pressure. Thecompressor outlet pressure may be computed using isentropic efficiency,compressor RPM, compressor inlet superheat, and compressor outlettemperature. The compressor outlet temperature which may be computed inStep 2 may then be moved to Step 3. Step 3 may be constructed andarranged to compute a compressor ratio. In order to compute thecompressor ratio, Step 3 may use the compressor inlet pressure and mayadditionally use the compressor outlet pressure. The compressor ratiomay be transferred to Step 4. Additionally, Step 4 may includeadditional input of a compressor volumetric efficiency which may bedirectly or indirectly sensed or measured in the system. AdditionallyStep 4 may also compute the compressor flow. The compressor flow may becomputed using compressor inlet pressure, compressor superheat,compression ratio, and compressor volumetric efficiency. The compressorflow may then be inputted into Step 5. Step 5 may be constructed andarranged to compute a compressor torque. The compressor torque may becomputed by using the compressor ratio, compressor RPM, compressor flow,and compressor inlet pressure. The compressor torque may then bepopulated and may be evaluated.

It is contemplated that the controller may be additionally oralternatively constructed and arranged to include a combo sensorevaporator capacity control algorithm. The combo sensor evaporatorcapacity control algorithm may be constructed and arranged to providedata which may be useful in determining and controlling the workingfluid and/or other components of the system. It is contemplated that inStep 1, inputs may include but are not limited to compressor inletpressure, compressor inlet temperature, compressor outlet pressure andblower speed may be used. The inputs from Step 1 may be entered intoStep 2. The inputs may then be used in Step 2 in order to computesuction pressure drop. The suction pressure drop may be computed usingvehicle speed, compressor outlet pressure, compressor inlet pressure,and hose configuration calibration. Next, in Step 3, the rolling averageevaporator outlet pressure may be computed. The rolling averageevaporator outlet pressure may be computed using compressor outletpressure suction line pressure drop and calibration C time frame. Thecomputed rolling average evaporator outlet pressure computed in Step 3may be inputted into Step 4. It is contemplated that Step 4 may computea freeze target pressure. The freeze target pressure may be computedusing the evaporator outlet pressure, the compressor outlet pressure,the compressor outlet temperature, suction line pressure drop, andblower speed. It is contemplated that Step 5 may be a logic step. Step 5may determine whether the rolling average evaporator outlet pressure isabove the freeze target pressure. If the rolling average evaporatoroutlet pressure is above the freeze target pressure then the compressorcontrol may be reset and Steps 2-5 may be repeated. However, if therolling average evaporator outlet pressure is not above the freezetarget pressure, it is contemplated that the controller may beconstructed and arranged to incrementally increase the compressorcontrol pressure up by approximately 10 kPA. Once the compressor controlpressure has been raised, Steps 2-5 may be repeated.

It is also contemplated that the controller may additionally oralternatively include a combo sensor low charge algorithm. The combosensor low charge algorithm may include a first step which includes theinputs of compressor inlet pressure and temperature. Next in Step 2, thecompressor inlet pressure and the compressor inlet temperature may beused to compute the compressor inlet superheat. The compressor inletsuperheat may then be moved to Step 3. It is contemplated that Step 3may include computing the rolling average of the compressor inletsuperheat. It is contemplated that the rolling average compressor inletsuperheat may be computed using a calibration time frame. Next, therolling average compressor inlet superheat may be moved to Step 4, it iscontemplated that Step 4 may be a decision step. It is contemplated thatif the rolling average compressor inlet superheat is above a low chargesuperheat max which may be a constant known by one of ordinary skill inthe art, then the loop may continue onto Step 5. However, if the rollingaverage compressor inlet superheat is not above the low charge superheatmax then Steps 2-4 may be repeated. Once it is determined that therolling average compressor inlet superheat is above the low chargesuperheat max, Step 5 may be another decision step. It is contemplatedthat Step 5 may compare the rolling average compressor inlet superheatto the EATA (Evaporator Air Temperature Average) max. In Step 5, if therolling average compressor inlet superheat is above the EATA max, theclutch may be disabled for up to approximately 60 seconds. However ifthe rolling average compressor inlet superheat is not above the EATA maxthen the loop may continue onto Step 6. It is contemplated that Step 6may be an additional decision or comparison step. In Step 6, it iscontemplated that if the EATA is higher than the EATA maximum then theloop has reached its end. However, if the EATA is not higher than theEATA maximum, the EATA may be incremented upward by approximately 1degree. Once the EATA is raised by approximately 1 degree, the loop maybegin again at Step 2. It is contemplated that the EATA may be resetduring calibration. Additionally it is contemplated that the EATA max atOAT (Outside Ambient Temperature) is OAT.

It is contemplated that the combo sensor compressor torque algorithm,the combo sensor evaporator capacity control algorithm, and the combosensor low charge algorithm may be used simultaneously with one another,consecutively, or in any combination as desired by one of ordinary skillin the art. Additionally it is contemplated that each of the algorithmsmay be used singularly or in any combination with one another as desiredby one of ordinary skill in the art.

It is contemplated that the variation illustrated in FIG. 1 may improvethe efficiency of the refrigeration circuit 10. Moreover, evaporatorcore freeze detection may be immediately detected and remedied thereforethe core freeze condition may be monitored more closely and directly.Additionally, the variation illustrated may eliminate the need for anevaporator air temperature (EAT) sensor and may also potentiallyeliminate a high side pressure sensor which may be disposed in prior artsystems.

In operation, the working fluid may flow through the liquid line 46 tothe expansion valve 53 to drop the pressure and temperature then mayflow into the evaporator 14 where the evaporator 14 may change the phaseof the working fluid from a liquid and vapor mixture to a vapor in orderto gain heat. The vapor may then be moved through the suction line 18 tothe compressor 16. The suction line 18 may include at least one sensorincluding a pressure sensor 20, a temperature sensor 22, a combinationsensor or other sensors as known by one of ordinary skill in the art.The information determined by the sensors in the suction line 18 may besent to a controller which may then control the speed and othercharacteristics of the working fluid. From the suction line 18, theworking fluid may be transferred through the compressor 16 and out to adischarge line 42. The discharge line 42 may be free of sensors or mayinclude a temperature or other sensor. Again, any information gatheredby the sensors may be sent to the controller for further control of theworking fluid. Next, the working fluid may flow from the discharge line42 through the condenser 12. The condenser 12 may be constructed andarranged to change the phase of the working fluid from a gas to aliquid. The condenser 12 may include an outlet 52 and the outlet may beoperably coupled to the liquid line 46 which then may enter into theevaporator 14 to begin the cycle again. The pressure and temperature inthe suction line 18 may be taken at any time prior to the beginning ofthe circuit, during operation of the circuit or after operation of thecircuit as known by one of ordinary skill in the art.

The following description of variants is only illustrative ofcomponents, elements, acts, product and methods considered to be withinthe scope of the invention and are not in any way intended to limit suchscope by what is specifically disclosed or not expressly set forth. Thecomponents, elements, acts, product and methods as described herein maybe combined and rearranged other than as expressly described herein andstill are considered to be within the scope of the invention.

Variation 1 may include a refrigeration circuit which may include acondenser operably coupled to an evaporator along with a compressoroperably coupled to the evaporator using a suction line, wherein thesuction line may include a pressure sensor and a temperature sensor.

Variation 2 may include a refrigeration circuit as set forth invariation 1 further comprising a controller constructed and arranged todisable a clutch during a low charge condition.

Variation 3 may include the refrigeration circuit as set forth in any ofvariations 1 to 2 wherein the controller includes an algorithm todetermine whether the circuit is in a low charge condition.

Variation 4 may include the refrigeration circuit as set forth in any ofvariations 1 to 3 wherein a temperature sensor may be disposed in thedischarge line.

Variation 5 may include the refrigeration circuit as set forth in any ofvariations 1 to 4 wherein the temperature sensor may be the only sensordisposed in the discharge line.

Variation 6 may include the refrigeration circuit as set forth in any ofvariations 1 to 5 wherein temperature and pressure may be measureddirectly in the suction line.

Variation 7 may include the refrigeration circuit as set forth in any ofvariations 1 to 6 wherein the pressure sensor and the temperature sensormay be a single combination sensor which may be constructed and arrangedto directly measure both pressure and temperature in the suction line.

Variation 8 may include a system which may include a condenser operablycoupled to an evaporator via a liquid line and expansion valve alongwith a compressor operably coupled to the evaporator via a suction line,wherein a pressure sensor and a temperature sensor may be disposed inthe suction line.

Variation 9 may include the system as set forth in any of variations 1to 8 further comprising a controller.

Variation 10 may include the system as set forth in any of variations 1to 9 wherein the controller may be constructed and arranged to use analgorithm to determine a torque of the compressor.

Variation 11 may include the system as set forth in any of variations 1to 10 wherein the temperature sensor may be disposed in the dischargeline.

Variation 12 may include the system as set forth in any of variations 1to 11 wherein the temperature sensor may be the only sensor disposed inthe discharge line.

Variation 13 may include the system as set forth in any of variations 1to 12 wherein the temperature and pressure may be directly measured inthe suction line.

Variation 14 may include the system as set forth in any of variations 1to 13 wherein the pressure sensor and the temperature sensor may be asingle combination sensor constructed and arranged to directly measureboth pressure and temperature.

Variation 15 may include a method which may include providing arefrigeration circuit comprising a condenser operably coupled to anevaporator and a compressor operably coupled to the evaporator via asuction line and measuring both a pressure and temperature directly inthe suction line.

Variation 16 may include the method as set forth in variation 15 whereina controller may be constructed and arranged to control flow in therefrigeration circuit.

Variation 17 may include the method as set forth in any variations 15 to16 further comprising determining a torque of the compressor using thepressure and temperature of the suction line.

Variation 18 may include the method as set forth in any of variations 15to 17 wherein the pressure sensor and the temperature sensor may be asingle combination sensor constructed and arranged to directly measureboth pressure and temperature in the suction line.

Variation 19 may include the method as set forth in any of variations 15to 18 further comprising disabling a clutch when it is determined thatthe circuit may be in a low charge mode.

Variation 20 may include the method as set forth in any of variations 15to 19 wherein the condenser and the evaporator may be operably coupledby a liquid line.

The above description of select variations within the scope of theinvention is merely illustrative in nature and, thus, variations orvariants thereof are not to be regarded as a departure from the spiritand scope of the invention.

What is claimed is:
 1. A refrigeration circuit comprising: a condenseroperably coupled to an evaporator; a compressor operably coupled to theevaporator using a suction line, wherein the suction line includes apressure sensor and a temperature sensor.
 2. The refrigeration circuitof claim 1, further comprising a controller constructed and arranged toreduce the compressor capacity or disable a clutch during a low chargecondition.
 3. The refrigeration circuit of claim 1, wherein thecontroller includes an algorithm to determine whether the circuit is ina low charge condition.
 4. The refrigeration circuit of claim 3, whereina temperature sensor is disposed in the discharge line.
 5. Therefrigeration circuit of claim 4, wherein the temperature sensor is theonly sensor disposed in the discharge line.
 6. The refrigeration circuitof claim 1, wherein temperature and pressure are measured directly inthe suction line.
 7. The refrigeration circuit of claim 1, wherein thepressure sensor and the temperature sensor are a single combinationsensor constructed and arranged to directly measure both pressure andtemperature in the suction line.
 8. A system comprising: a condenseroperably coupled to an evaporator via a liquid line and expansion valve;a compressor operably coupled to the evaporator via a suction line,wherein a pressure sensor and a temperature sensor are disposed in thesuction line.
 9. The system of claim 8, further comprising a controller.10. The system of claim 8, wherein the controller is constructed andarranged to use an algorithm to determine a torque of the compressor.11. The system of claim 10, wherein a temperature sensor is disposed inthe discharge line.
 12. The system of claim 8, wherein a temperaturesensor is the only sensor disposed in the discharge line.
 13. The systemof claim 8, wherein temperature and pressure are measured directly inthe suction line.
 14. The system of claim 8, wherein the pressure sensorand the temperature sensor are a single combination sensor constructedand arranged to directly measure both pressure and temperature.
 15. Amethod comprising: providing a refrigeration circuit comprising acondenser operably coupled to an evaporator via a liquid line andexpansion valve and a compressor operably coupled to the evaporator viaa suction line; measuring both a pressure and temperature directly inthe suction line.
 16. The method of claim 15, wherein a controller isconstructed and arranged to control flow in the refrigeration circuit.17. The method of claim 16, further comprising determining a torque ofthe compressor using the pressure and temperature of the suction line.18. The method of claim 15, wherein the pressure sensor and thetemperature sensor are a single combination sensor constructed andarranged to directly measure both pressure and temperature in thesuction line.
 19. The method of claim 15, further comprising reducingthe capacity or disabling a clutch when it is determined that thecircuit is in a low charge mode.
 20. The method of claim 15, wherein thecondenser and the evaporator are operably coupled by the liquid line andthe expansion valve.